Computer system electronic components include mainboards, daughter boards, processors, cards, and various other modules. It can be appreciated that shock and vibration can damage such system components.
Vibrations may cause system failure in a number of ways. Vibration may fatigue electronic components, causing failure. Vibrations may also loosen connections between electronic components, making the computer system more likely to malfunction. Vibrations experienced by a typical computer system include vibration caused by hard disk drives. These vibrations are caused by the rotating disk drive platter and tend to be relatively high in frequency. Moreover vibrations can be amplified in systems having a number of disk drives operating simultaneously. Worn or damaged disk drive bearings are another source of undesired vibration. These and other vibrations can shake apart solder joints and may fatigue computer system components.
Shock is another adverse condition that can cause the computer system to malfunction. Sudden shock may be caused by impact between the computer housing and another object, for example. Sudden shock may flex the housing, or cause the electronic components to shift, causing damage to the electronic components.
During a sudden shock such as from an impact, the computer housing will flex. Flexion of the housing is a concern because such flexion may, in turn, deform the electronic components causing damage or misalignment of connected components including the mainboard. Flexion of the mainboard is particularly troublesome because such flexion may damage not only the mainboard, but may also the various components which attach to the mainboard, and connections between these components. There are numerous other ways in which shock may adversely effect electronic components.
The magnitude of any shock or vibration is not always indicative of the amount of damage the shock or vibration inflicts. Other factors influence the amount of damage. These factors include how the shock or vibration resonates. A computer housing may magnified and/or dampened any particular the shock or vibration depending on the shape and structure of the housing.
The frequency of shock or vibration also influences the extent that shock or vibration will damage a system. A high frequency vibration, commonly generated by disk drives, may damage other electronic components. Sudden shock from impact may damage the disk drives. Dampening high frequency vibrations, however, may not significantly dampen low frequency impacts. Both high and lower frequency vibrations in a computer housing should be dampened by the housing.
Some computer systems have casters. Casters enable people to more easily move the computer system within a room, between rooms, or even between buildings. Casters, however, may increase the probability that any particular computer system will be moved--raising the likelihood that the system will endure impact. Impact with door jams, walls, and even the knee of a passerby is more likely when a system is moved. Furthermore, casters may communicate undesired vibrations to the computer housing during movement of the computer system. Such impacts often cause a sensitive electronic component to loosen or break. Vibrations due to movement over a rough surface (i.e. parking lot) may also cause component failure.
Therefore, it is desirable to provide a computer housing which is resists impact and which dampens high frequency vibrations. It is also desirable to provide a rugged computer system having casters so that the system is moveable without seriously risking computer system failure.